The invention relates to a mounting unit for a drive shaft of a motor vehicle and a combination of a motor vehicle including the mounting unit. In this case, the mounting unit comprises a drive shaft holder, also referred to as a drive shaft bracket, for fastening at least one drive shaft to a mounting component, such as the engine block of the motor vehicle.
In order to increase the occupant safety in passenger motor vehicles, in particular, in the case of frontal impacts, various measures are known in which components in a front region of a vehicle are collapsed when predefined impact forces are exceeded, so as to permit a controlled deformation of parts in the front region of the vehicle. Thus, the forces from the impact are not transferred into the interior of the vehicle and deformation of the interior of the vehicle is minimized.
In one case it has been suggested that the components of a drive shaft should be collapsed in the axial direction in a collision. For example, drive joints which comprise an inner hub and an outer hub are disclosed in U.S. Pat. No. 8,157,658 B2. When a specific axial force on a drive joint is exceeded, the outer hub breaks open such that a crack is produced in the outer hub. The crack begins at one location and extends at least approximately in the radial direction. The crack permits the inner hub to be disengaged from the outer hub.
GB 2 358 902 A proposes a drive shaft which is collapsible in an axial direction and which is formed in one piece. The drive shaft has a uniform normal diameter but also has at least one compression zone formed by locally altering the diameter of the drive shaft. This compression zone has three different regions. In a first compression introduction region, the diameter of the drive shaft is slightly enlarged so that a local outwardly bulged portion is produced. A further, second region is joined to the first region. The diameter in the second region is also larger than the normal diameter of the drive shaft but smaller than the diameter in the compression introduction region. The diameter is further reduced from this second region to the normal diameter, forming a third region with a conical shape. U.S. 2003/0079327 A1 also discloses a collapsible drive shaft and, more particularly, discloses a method for producing such a drive shaft. JP 2002-002527 A also proposes a compressible component in the region of a drive shaft.
WO 2011/101952 A1 proposes a solution in which a drive shaft is deformed in a controlled manner in the event of a side impact, such that the drive shaft does not come into contact with other components of the vehicle. In this manner, the drive shaft does not damage the passenger compartment. To this end, a deformation guidance element is provided. In the event of an impact, the deformation guidance element forces the drive shaft in a specific direction. This preferably produces a downward deformation in the direction of the ground.
Drivetrains and engines of motor vehicles are becoming larger in size since they have to accommodate an increasing number of additional components, such as exhaust gas treatment devices, air-conditioning compressors, electric generators, etc., to fulfill new requirements. As a result, the number and size of non-deformable parts in the front region of the vehicle is increasing. Thus, the front of the vehicle has to be lengthened in order to maintain consistent safety performance as the additional components are added. This is often not desirable, however, for design reasons or due to other preset requirements for the vehicle.
Moreover, different types of drive shafts are used. For example, a front wheel drive vehicle drivetrain could include particular drive shafts such as an intermediate shaft, usually referred to as a link shaft, and equal length drive shafts, usually referred to as half shafts. Alternatively, the front wheel drivetrain drive could include two shafts without an intermediate shaft, in which case there would be two shafts of unequal length. This situation results in different drive units with different surrounding components, which has an affect on safety-relevant properties. The different systems result in an increase in the complexity, development effort and costs when designing ways to provide occupant safety in the event of a collision.
Regardless of the prior art described above, increasing the occupant safety in motor vehicles with increasingly large drivetrains is an area, which leaves further room for improvement. In particular, the pedal board, also referred to as a toeboard, being pressed in or deformed by components of the drivetrain in the event of a collision, represents an area where further improvements would be advantageous.
The object of the invention, therefore, is to provide a system in a motor vehicle by which the occupant safety in the event of a collision, in particular in the region of the toeboard, may be increased and to provide a system that functions independent of the type of drivetrain.